The vigour of the people will depend largely upon the conditions under which they live, upon sufficiency of food, the healthiness or otherwise of their employments and homes, the proper nourishment and upbringing of their children. It is not enough that rates of wages should be good, if those who earn them {224} have not the knowledge how to use them to the best advantage. It is not always where incomes are lowest that the conditions of life are worst. Measured by infant mortality, and by the health and general happiness of the community, the crofters of Scotland, who are very poor, seem to have learned the lesson _how to live_ better than the highly paid workers in many of our great manufacturing towns. Education--by which is meant not merely board-school instruction, but the influence of the home and the surrounding society--is not a less necessary condition of vigour than wages, sanitary regulations, and such like. The spiritual as well as the physical training of children, the nature of their amusements, the bent of their interests, the character of their aims and ideals, at that critical period when the boy or girl is growing into manhood or womanhood--all these are things which conduce directly, as well as indirectly, to the vigour of the race. They are every bit as much a part of our system of national defence as the manoeuvring of army corps and the gun-practice of dreadnoughts. The _spirit_ of the people, on the other hand, will depend for its strength upon their attachment to their own country; upon their affection for its customs, laws, and institutions; upon a belief in the general fairness and justice of its social arrangements; upon the good relations of the various classes of which society is composed. The spirit of national unity is indispensable even in the case of the most powerful autocracy. It is the very foundation of democracy. Lacking it, popular government is but a house of cards, which the first serious challenge from without, or the first strong outburst of {225} discontent from within will bring tumbling to the ground. Such a feeling of unity can only spring from the prevalence of an opinion among every class of the community, that their own system, with all its faults, is better suited to their needs, habits, and traditions than any other, and that it is worth preserving, even at the cost of the greatest sacrifices, from foreign conquest and interference. [Sidenote: A TWO-HEADED PRINCIPLE] While a people sapped by starvation and disease will be wanting in the _vigour_ necessary for offering a prolonged and strenuous resistance, so will a people, seething with class hatred and a sense of tyranny and injustice, be wanting in the _spirit_. The problem, however, of these unorganised defences, fundamental though it is, stands outside the scope of the present chapter, which is concerned solely with those defences which are organised.